The present invention relates generally to spatial light modulators, and more particularly to a method for fabricating a hybrid multiple quantum well (MQW) based spatial light modulator.
The MQW spatial light modulator is a potentially high speed modulator for optical signal processing, adaptive optics and infrared to visible conversion applications. Existing MQW spatial light modulator devices are monolithic, which imposes severe limitations on material selection and device fabrication, and usually incorporate submicron grids as reflecting mirrors, which allows light leakage resulting from polarization state variation. An alternative device includes a dielectric mirror which has the disadvantage advantage of both incident angle and operating wavelength dependence. The present invention provides a method for fabricating a hybrid MQW based spatial light modulator wherein an MQW modulator and driver are fabricated separately, so that any high temperature processing steps in the fabrication of either will not adversely affect the structure or operation of the other, and then assembled with a mirror therebetween deposited on a surface of the MQW modulator to minimize light leakage in the assembly. The modulator and driver are then pixelized in the assembled condition to provide lateral resolution to the assembly and to avoid alignment problems in the assembly process. A modulator device according to the method described herein can be fabricated from different material systems such as a silicon driver and GaAs/GaAlAs modulator, unlike the monolithic structure which normally requires the same material system to achieve lattice match. The invention can be operated at extremely high speed (greater than one GHz) at medium voltage (less than 100 volts), which operating characteristics are not available in other known types of spatial light modulators.
It is therefore a principal object of the invention to provide a method for fabricating an MQW based spatial light modulator.
It is a further object of the invention to provide a method for fabricating a MQW spatial light modulator comprising an assembly of a modulator and photodriver.
These and other objects of the invention will become apparent as the detailed description of representative embodiments proceeds.